FILE PHOTO - The word "Yen" is pictured on a Japanese banknote on top of a U.S. dollar bill at Interbank Inc. Money exchange in Tokyo, Japan in this September 9, 2010 picture illustration. REUTERS/Yuriko Nakao/File Photo

TOKYO (Reuters) - The dollar dropped to a four-month low against the yen early on Tuesday after the Japanese and South Korean governments said North Korea had fired a missile that passed over northern Japan.

The dollar was down 0.5 percent at 108.725 yen after hitting 108.330, its lowest since April 18.

The greenback was already on the defensive, particularly against the euro, after Federal Reserve Chair Janet Yellen did not mention monetary policy at a central bankers’ summit in Jackson Hole last week, and as European Central Bank President Mario Draghi’s held back from talking down the euro at the same meeting.

The euro was down 0.1 percent at $1.1965 following an ascent to $1.1986, its highest since January 2015.